考點:整數(shù)四則混合運算,運算定律與簡便運算
專題:運算順序及法則
分析:(1)把495看作500-5,然后再根據(jù)減法的性質進行簡算;
(2)把397看作400-3,然后再根據(jù)加法交換律進行簡算;
(3)根據(jù)加法交換律和結合律進行簡算;
(4)根據(jù)減法的性質進行簡算;
(5)根據(jù)減法的性質進行簡算;
(6)先算小括號里面的加法,再算括號外面的加法;
(7)先算乘法,再算減法;
(8)按照從左向右的順序進行計算.
解答:
解:(1)563-495
=563-(500-5)
=560-500+3
=60+3
=63;
(2)397+656
=(400-3)+656
=400+656-3
=1056-3
=1053;
(3)391+568+709+32
=(391+709)+(568+32)
=1100+600
=1700;
(4)1937-672-937
=1937-937-672
=1000-672
=328;
(5)1249-(673+249)
=1249-673-249
=1249-249-673
=1000-673
=327;
(6)7589+(3565+231)
=7589+3887
=11385;
(7)1236-185×6
=1236-1110
=126;
(8)482-188+118
=294+118
=412.
點評:考查了運算定律與簡便運算,四則混合運算.注意運算順序和運算法則,靈活運用所學的運算定律簡便計算.